Process and device for forming the winding cores of stators or rotors of electric machines

ABSTRACT

A process and device for forming the winding core of a stator or rotor. The winding core is only partially exposed to shaping pressure. Shaping is then continued progressively over the core periphery. A device for effecting the method includes a single or multipartite pressing tool for the winding core. The tool is rotatable relative to the long axis of a stator or rotor. In a preferred embodiment, the tool has a narrow shaping part positioned adjacent to a wrapping tool used to provide a wrapping about the shaped coil.

This is a division, of application Ser. No. 49,305 filed June 18, 1979,now U.S. Pat. No. 4,327,478 granted May 4, 1982.

The invention concerns a process for forming the winding cores alsocalled winding heads of stators or rotors of electric machines, as wellas a device for execution of the said process.

There are various processes for fastening the winding cores, and in thisway protecting them against damage. One of the conventional methods is"lacing" whereby the winding cores are manually or mechanically boundfirmly together by looping cotton strips, fiberglass strips, cords orthe like around them. In the mechanized production of motors, thecustomary process usually includes preshaping of the windings pulledinto a stator in the region of the winding cores that project at thefront beyond the stator sheet pack, lacing them, and finallystraightening the laced winding cores precisely, in a second pressing orshaping step.

In the known processes and devices, the winding cores are subjected toeffective pressure simultaneously, over the whole periphery, by annulartools. There is the drawback associated with this, that the shapingforces that are to be applied and to be received by the machineconstruction are relatively great. Another disadvantage is that theshaping and lacing processes occur in succession. The preshaped windingcores then partly jump up because of their intrinsic elasticity, beforethey are laced and then they cannot be tied firmly and they loosen stillmore with the after-shaping in the lacing, so that during lateroperation of the motor, intrinsic motions and oscillations of individualwires that may occur can then lead to fracture.

The invention is intended to develop a process and a device suitable forits execution, by means of which the winding cores can be shaped withless force. To solve this problem, it is proposed that the winding coresbe only partly exposed to shaping pressure, and progressively shapedover the periphery.

Since, according to the process of the invention, greater pressure isexerted only on a small place, the forces to be utilized are slight,whereas the pressing effect is very good.

Although in principle the new process can be applied in all cases inwhich winding core are preshaped and/or finally shaped, whether in aspecial work step or in direct temporal connection with a work step thatfastens the winding cores, in a preferred embodiment of the invention,the winding cores will be laced during shaping, whereby advantageouslythey are only shaped close the lacing station, and therewithprogressively shaped by strong pressure. In this way, it is ensured thatthe wire in the winding core cannot work loose between the shaping andthe lacings.

In a further preferred embodiment of the process of the invention, thewinding cores are pressed together with strong pressure only justupstream of the lacing station. Downstream of the lacing station, theyare held by the lacings.

In the present process, it is possible in most cases to do without anyfurther forming processes.

A device is proposed for carrying out the process according to theinvention, which has a single or multipartite pressing tool for thewinding cores. The tool is rotatable relative to the long axis of thestator or rotor, and in a preferred arrangement, it has a narrow shapingpart immediately next to a lacing tool, the narrow shaping part beingprogressively movable with the tool relative to a winding undergoing ashaping process.

The above expression "narrow shaping part" means a shaping part that isno wider than necessary in view of considerations of strength, wear,possibility for attachment, and other technological factors, to compressthe winding cores in the region where the lacing tools work.

The shaping part can have an essentially U-shaped profile in a radialsectional plane with reference to the stator or rotor. However, in analternative embodiment, it may comprise one or more rolls that pressradially and/or axially against the winding core. In a further practicalmodification of the concept of the invention, the shaping part may alsobe made like tongs or in another suitable way, so that it can be variedin cross-section in a radial plane of the stator or rotor.

To prevent the winding cores from being pressed so closely against thefront face of the stator sheet pack by axial shaping pressure orpossibly by axial pressure combined with radial shaping pressure, thatthe lacing tool will be unable to be introduced between the windingcores and the stator sheet pack, in a preferred embodiment of theinvention, it may be provided that the shaping part will cooperate withsupporting members that can be introduced between the winding cores andthe front of the stator or rotor, which supporting members will retain aspecific separation between the winding cores and the front of thestator or rotor. The said supporting members can be nose-shaped ortongue-shaped projections, on a retaining device of the stator sheetpack.

The proposed shaping part is advantageously placed on a known ringtrough that receives and shapes the annulus of the winding cores, beinginterrupted in the region of the lacing tool. As before, the lacing toolis supposed to prepare the wires of the winding cores and also anyinserted insulation, without application of strong pressing pressureduring the lacing.

The invention is discussed below with reference to the drawings.

FIG. 1 is a perspective view of the essential part of the device of theinvention, for shaping the winding cores that are to be laced.

FIG. 2 is a schematic cross-section through a stator with its windingand a shaping part that compresses the winding cores next to the lacingstation.

FIG. 3 is a cross-section through the shaping part shown in FIG. 2, in asectional plane perpendicular thereto, whereby the stator sheet pack andthe winding cores are shown schematically as a kind of developedprojection.

FIGS. 4 and 5 are views corresponding to FIG. 2, of two modified devicesfor shaping the winding cores.

FIG. 6 is a cross-section corresponding to FIG. 3, through the shapingpart shown in FIG. 5.

The invention can be utilized with a lacing machine of the typedescribed, for instance, in German Patent No. 1,203,873. Other similarlacing machines are shown in German OS Nos. 2,206,657; 2,407,557;2,408,244; 2,437,452; and 2,637,909. What is involved here for theinvention is not the lacing tools and the lacing process in particular,but rather the compression of the winding cores that are to be laced,directly during the lacing.

The shaping tool shown in FIG. 1 is provided for this purpose. Itconsists in principle of a mandrel 10 that can be introduced into thehole of the stator sheet pack, this arrangement not being absolutelynecessary, however, and an annular flange 12 that can be set thereon,with an annular tray 14 formed therein, in which upon introduction ofmandrel 10 into the hole of the stator sheet pack, are disposed thewinding cores that project unilaterally. On the opposite axial side ofthe stator sheet pack, there can be another shaping device 10, 12 ofthis kind, to allow shaping of the stator on both sides and lacingsimultaneously.

Annular flange 12 has a cut 16 at one location on its periphery,penetrating through to mandrel 10, in which the lacing tool (notillustrated) operates. The latter, during the lacing, executes astepwise turning together with shaping tool 10, 12 relative to thestator sheet pack and the annulus of the winding core, whereby thelacing tools respectively pass into the space between the stator groovesthat receive the windings, between the winding cores and the front faceof the stator sheet pack, and thereby the lacing cord is pulled alongand tied firmly about the winding cores by looping and knotting.

In order that the winding cores may be firmly compressed in the desiredform during the lacing, shaping tool 10, 12 could be made with asuitable profiling of annular tray 14, and pressed with great forceagainst the winding cores. The whole machine construction would have tobe correspondingly heavy and expensive in its design. The inventiontherefore provides that the winding cores will be compressed with greatpressing force only in a relatively narrow area directly next to theplace at which the lacing tools work, and for this purpose, use is madeof a special shaping part 18 disposed on the edge of the notch or cut 16in annular flange 12. The arcuate profile of the shaping tool 18 thatengages the winding cores has less depth and radial width than annulartray 14. In this way, shaping part 18 presses substantially morestrongly than the wall of annular tray 14 against the winding cores. Inturning of shaping tool 10, 12 relative to the stator sheet pack in thedirection indicated by arrow 20 in FIG. 1, shaping tool 18 moves closeahead of the lacing tools and presses the winding cores directly at thelacing station in question, strongly and in the desired shape.

FIG. 2 shows how shaping part 18 engages winding core 22 like a U. Inthis way, pressure is exerted on the cores radially from inside and out,as well as axially from the outside. To prevent winding cores from beingpressed flat against the front face of the stator packet 24 of FIGS. 2and 3, where, for example, slot insulation 26 could be damaged, radialprojections or tongues 30 projecting inwardly could be disposed on aretaining device 28 for the stator sheet pack on its front, consistingfor example of two half shells, said projections engaging the windingcores 22 and bracing them against the shaping and compression pressureof shaping part 18 and ensuring a certain separation between the windingcores and the front face of the stator sheet pack that is needed for theorderly operation of the lacing tools.

FIG. 3 shows the deformation of the winding cores by shaping tool 18, ina cross-section tangential to the winding cores. To the left of shapingpart 18 is the as yet unlaced part of a winding core, whereas on theright the core has already been laced and thereby remains firmlycompressed.

As FIG. 3 shows, shaping part 18 should have the gentlest possiblerounded profile in the cross-sectional plane illustrated there, becausewith strong pressure it slides over the wires of the winding cores butmust not damage them. Alternatively, therefore, shaping part 18 may bein the form of one or more rollers, or a lever, or a tong-like member.Reference is made in this connection to FIGS. 4 to 6.

According to FIG. 4, a lever 32, borne on a shaft 34 on annular flange12 serves as shaping tool. Lever 32 is kept in constant application tothe periphery of a rotationally driven cam plate 38, by a spring 36.Thereby lever 32, during the stepwise turning of shaping tool 18relative to stator 24 will be alternatingly pressed against winding core22 and retracted radially outward.

In the arrangement according to FIG. 4, lever 32 presses essentiallyradially from the outside inward against the winding core. Theconfiguration and/or arrangement of lever 32 or other levers can be soselected however, that the pressing force exerted on the winding coreand locally deforming it will act axially.

The arrangement according to FIG. 5 differs from that of FIG. 4 in thatthe lever 32 cooperates like tongs with another lever 40. A single camplate 38 suffices as a drive if lever 32 and lever 40 are engaged via atoothed arrangement 42. A spring 44 tensioned between the two serves torelease the tongs grip of levers 32 and 40. The levers act radially fromthe inside and outside on winding core 22. Depending upon theconfiguration and arrangement of the levers, there may also be exertionof an axial pressing force, at the same time as the radial pressingforce.

A special device is provided according to FIG. 5 to obtain an axialdeformation of winding core 22. Levers 32, 40 are not borne on annularflange 12, but on a retaining device 46 that is axially swingable withreference to the stator axis, said device 46 in turn being borne on apivot pin 48 and swingable in the direction indicated by the arrow bythe drive coupled with the drive of cam plate 38, acting via gears 50,52. With this kind of shaping device, winding core 22 receives thecorrugated surface shown in FIG. 6.

Other modifications of the shaping tool are possible within the scope ofthe invention. In one modification the device 46 could swing against thewinding core only once and keep their position while the levers 32, 40alternatively press and open during the forming and lacing process.

What is claimed is:
 1. A device for shaping and lacing the winding headof a stator or rotor of an electrical machine comprising a shaping toolincluding a shaping part for shaping a said winding head of a stator orrotor, means for rotating said shaping tool relative to the longitudinalaxis of the stator or rotor, and lacing tool means for lacing saidwinding head simultaneously with said shaping of said winding head, saidshaping tool being disposed immediately adjacent to said lacing toolmeans and being progressively movable with the lacing tool means aroundthe circumference of the winding head.
 2. A device as in claim 1,wherein said shaping part is disposed upstream of the lacing tool, inthe direction of movement relative to a stator or rotor.
 3. A device asin claim 1, wherein said shaping part presents an essentially U-shapedprofile in a radial sectional plane with reference to a stator or rotor.4. A device as in claim 1, wherein said shaping part comprises at leastone roll.
 5. A device as in claim 1, wherein said shaping part isvariable in cross-section in a radial plane of a stator or rotor.
 6. Adevice as in claim 1, wherein the shaping part comprises a pair oftong-like lever members.
 7. A device as in claim 1, wherein said shapingpart comprises a first member that acts radially and a second memberthat acts axially.
 8. A device as in claim 1, comprising spring meansfor pressing said shaping part against a winding head.
 9. A device as inclaim 1, comprising a plurality of increasingly effective shaping partsdisposed in staggered arrangement axially relative to a rotor or stator.10. A device as in claim 1, further comprising supporting members andmeans for introducing said supporting members between the winding headsand the face of a stator or rotor for maintaining a specific separationbetween the winding heads and the front of a stator or rotor.
 11. Adevice as in claim 1, wherein said shaping tool comprises an annulartray that receives and preshapes the annulus of a winding core, and saidshaping part is disposed thereon, said tray being interrupted in theregion of the lacing tool means.
 12. A device as claimed in claim 11,wherein said interruption comprises a radial slot in said tray.
 13. Adevice as in claim 1, comprising a plurality of shaping tools, withshaping parts for axially opposed winding cores.
 14. A device as inclaim 1, comprising a plurality of increasingly effective shaping partsdisposed in a staggered arrangement in radial relationship to the saidrotor or stator.
 15. A device as in claim 1, wherein said shaping toolincludes a radial slot form therein for receiving said lacing toolmeans.
 16. A device as claimed in claim 1, wherein said shaping tool isdisposed so as to press in a direction against the face of the stator orrotor.